For many years, screw eyes have been used to enable wires to be fastened to the backsides of picture frames so that the frames may be hung from hooks on a wall. The conventional screw eye has a threaded shank and an integral closed eye. Since it must be rotated into the wooden frame, installation is labor intensive.
There is a need for hangers, such as screw eyes, which can be fastened to a wooden frame simply by being driven into place, as by a hammer, or which can be fed automatically from a magazine and driven, in the manner of a staple. Such hangers are particularly attractive to frame manufacturers because they are less labor intensive to install. While known drivable hangers are efficient to install, they have not been as satisfactory as desired because their shanks lack sufficient holding power for many applications.
To augment the holding power of a drivable shank, some have proposed the use of barbs on shanks, such as nails, rail spikes, staples and the like. Examples of barbed nails and spikes may be found in the following U.S. Pat. Nos. 318,566; 546,269; 911,273; 1,092,351; 2,373,311; and 2,649,831. Staples having barbed shanks are disclosed in U.S. Pat. Nos. 84,585 and 2,867,807. Miscellaneous fasteners having specially formed shanks are disclosed in U.S. Pat. Nos. 852,247 and 3,719,342. U.S. Pat. No. Des. 282,525, owned by the assignee of the present application, discloses an adjustable picture hanger having a pair of specially formed shanks adapted to be driven into a picture frame.
While each of the aformentioned patented articles may function satisfactorily for its intended purpose, there is a need for a picture hanger which can be driven into a wooden frame yet which can resist disengagement under most anticipated loading conditions.